Pension Benefit and Other Postretirement Benefit Plans (Summary of Changes in Fair Value of Guaranteed Deposit Account's Level 3 Assets) (Details) (Pension Benefits [Member], Guaranteed deposit account [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	4 Months Ended
	Apr. 30, 2013
Pension Benefits [Member] | Guaranteed deposit account [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 15,402	[1]
Realized gains (losses)	0	[1]
Unrealized gains relating to instruments still held at the reporting date	1,177	[1]
Purchases, sales, issuances and settlements (net)	13	[1]
Transfers in and/or out of Level 3	0	[1]
Ending Balance	$ 16,592	[1]

[1] This calculation was performed as of April 30, 2013 due to the pension freeze and we are not otherwise required to perform the calculation at interim periods